fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/switch.py b/Demo/tkinter/guido/switch.py
index 3b58f7c..3f43925 100644
--- a/Demo/tkinter/guido/switch.py
+++ b/Demo/tkinter/guido/switch.py
@@ -1,6 +1,6 @@
 # Show how to do switchable panels.
 
-from Tkinter import *
+from tkinter import *
 
 class App: